Abstract: This paper aims to investigate geological hazard precisely in strong seismic zone. It uses unmanned aerial vehicle based low-altitude photographic system. The system can obtain high-precision, high-resolution and high-altitude remote sensing image, and has the advantage of flexibility and freedom from complex topography. This paper applies the system to the precise investigation of geological hazard, the precise investigation procedure of geological hazard in strong seismic zone. The application of results are discussed. The paper takes the application in the Laohuzui landslide zone as an example. It describes the remote sensing image extraction and the method of DEM,DOM and three-dimensional real space scene. It focuses on introducing the qualitative and quantitative analysis of the geological hazard and the precise description. The practice results show that:(1) compared with the conventional remote sensing investigation method, this method not only obtains higher-resolution and higher-precision basic data for the precise investigation of the geological hazard, but also improves its efficacy and reliability; (2) three-dimensional real space scene of the geological hazard breaks through the traditional two-dimensional interpretation method, improves the precision and accuracy of the geological hazard. The system can be applied to the precise investigation of geological hazard in strong seismic zone.